NDIR Greenhouse Gas Monitoring System

Abstract

The present invention aims to provide a low-cost NDIR greenhouse gas monitoring device that combines a rotary multi-gas cell system and an NDIR sensor system for measuring nitrous oxide (N2O) gas at multiple locations in a short time. [Solution] The NDIR greenhouse gas monitoring device is characterized by comprising a rotary multiple gas cell system having two or more gas cells, gas cell holders that fix both ends of each gas cell, a central axis that serves as the axis of rotation of the gas cell holder, and a motor connected to the central axis that rotates the gas cell holder by rotating the central axis, and an NDIR sensor system having an NDIR light source unit, an NDIR detector unit, and a controller that controls the output of the motor that rotates the central axis in the rotary multiple gas cell system.

Description

Technical Field

[0001] The present invention relates to an NDIR greenhouse gas monitoring device for measuring greenhouse gases at multiple locations.

Background Art

[0002] The impact of greenhouse gases on the global environment is worsening year by year. Typical greenhouse gases, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases, are emitted from various sources (transportation, agriculture, households, commercial industries). The main causes of anthropogenic climate change are agriculture and food production. Therefore, in order to suppress greenhouse gas emissions, it is important to quantify the greenhouse gases emitted from agricultural operations and control the emission sources by continuously monitoring gas emissions from various production facilities.

[0003] Therefore, Patent Document 1 discloses a device for directly monitoring methane released from the nostrils of cows. Livestock are known to be an important source of methane gas emitted by exhalation and belching, and there are significant differences in the emission amounts among livestock. Therefore, the invention disclosed in this document can be used to measure and monitor the emission amounts of individual livestock.

[0004] However, with the invention disclosed in this Patent Document 1, continuous monitoring of gas emissions at multiple locations in agricultural fields cannot be performed. Moreover, since most of the conventionally known greenhouse gas measurement devices have only one gas cell, a valve operation system was required in the agricultural field where measurement at multiple locations is necessary.

[0005] The main steps for estimating the emission amount of greenhouse gases are temporal gas sampling from the source, measurement of gas concentration, and estimation of gas flux. There are two methods for obtaining gas samples from agricultural land: direct sampling and passive sampling. Direct sampling involves collecting gas samples from gas cells installed on the soil surface, while passive sampling involves collecting gas samples using diffused gas passing through gas-permeable or perforated tubes buried in the soil.

[0006] The direct sampling method employs the chamber method, which involves sampling gas samples directly from the soil surface through a permanently installed, sealed chamber. This method is suitable for small-scale cultivated land, as it involves setting up a simple chamber on the soil surface and circulating the sampled gas sample through a measuring device. The chamber method can only measure a narrow range in a single chamber; therefore, to measure a wide range, it is necessary to create multiple sampling points in multiple chambers.

[0007] Chambers can be broadly classified into two types based on their air circulation schedule: static chambers, which rapidly exchange the chamber gas while continuing measurements, and dynamic chambers, which store gas in the chamber for a certain period before performing scheduled ventilation.

[0008] However, in both methods, since low levels of gas concentration are dominant within the chamber rather than in the soil atmosphere, high-precision gas monitoring equipment is required, and considering the associated accessories, the cost of measurement increases.

[0009] Since soil gas concentrations are higher in the soil atmosphere than on the soil surface, low-cost equipment can be used for soil gas measurement. Therefore, the inventors have developed a low-cost NDIR greenhouse gas monitoring device for measuring the N2O concentration in soil gas using a gas sampling method with a soil-buried silicon diffusion cell. This device allows for the recording of N2O gas concentrations in soil over time.

[0010] However, due to the gas permeability characteristics of silicon diffusion cells, it takes several hours for the gas in the sampling cell to equilibrium with the soil gas concentration. Therefore, measurements must be taken continuously using a device with silicon diffusion cells connected in series, and it is not possible to ventilate the gas cells and switch between different gas sampling cells in a single device to measure multiple locations. In particular, in agricultural areas, it is necessary to measure gas concentrations at multiple locations.

[0011] For the reasons stated above, in order to more accurately estimate greenhouse gas emissions, it is necessary to develop a low-cost gas monitoring device that includes a gas sampling system capable of measuring at multiple locations. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Special publication 2023-507833 [Overview of the project] [Problems that the invention aims to solve]

[0013] Therefore, the object of the present invention is to provide a low-cost NDIR greenhouse gas monitoring device that combines a rotary multi-gas cell system and an NDIR sensor system for measuring gases at multiple locations in a short time. [Means for solving the problem]

[0014] The NDIR greenhouse gas monitoring device according to the present invention is Two or more gas cells are provided, each equipped with a gas inlet valve and a gas outlet valve, which are the gas inlet and outlet. A gas cell holder that secures both ends of each gas cell, The central axis that serves as the axis of rotation for the gas cell holder, A motor connected to the central axis, which rotates the gas cell holder by rotating the central axis, A chamber connected by a gas cell and a gas tube, A rotary multi-gas cell system having An NDIR light source unit consisting of an NDIR light source that emits infrared light and a plano-convex lens that condenses the light emitted by the NDIR light source, An NDIR detector unit consisting of an NDIR detector that detects infrared light, a plano-convex lens that condenses the light emitted by the NDIR light source that has passed through the gas cell, and an optical filter connected to the NDIR detector for the NDIR detector to detect the absorbance at each wavelength, A controller that controls the output of a motor that rotates the central axis in the rotary multi-gas cell system, An NDIR sensor system having Composed of Circulate gas between the gas cell and the chamber connected to the gas cell, By emitting and detecting infrared light with an NDIR light source and an NDIR detector, It is possible to measure the gas concentration in the chamber containing the gas to be measured at each measurement point [[ID=2)) Characterized by

Effect of the Invention

[0015] (1) In gas measurement at multiple locations, it can be measured more accurately than the conventional measurement method using a single gas cell. In particular, by using multiple gas cells, it becomes possible to monitor gases at multiple locations with fewer resources (excluding additional gas sampling units and valve systems). (2) When switching the gas for each measurement point, it becomes possible to measure simply by rotating multiple gas cells with chambers attached in advance, and there is no need to replace the gas in the gas cell. Therefore, the required observation time at one measurement point is short, and the gas can be switched in a short time. (3) By presetting the measurement schedule by a program, it is possible to automatically execute the gas concentration measurement of each gas cell at an arbitrary time interval, and there is no need to use a complicated valve system. <00000>>(4) Since a chamber can be attached in advance for each gas cell, an electromagnetic valve for switching gases at each measurement point is not required, enabling miniaturization and power saving.

Brief Description of the Drawings

[0016] [Figure 1] Schematic diagram showing the schematic configuration of a rotary multi-gas cell system [Figure 2] Substitute photograph of the drawing of the NDIR greenhouse gas monitoring device [Figure 3] Schematic diagram showing the NDIR optical path passing through the gas cell of the NDIR greenhouse gas monitoring device [Figure 4] Image diagram showing the time relationship in one cycle of measurement when the NDIR sensor system and the rotary multi-gas cell system are synchronized [Figure 5] Image diagram showing the installation position and rotation direction of the gas cell [Figure 6] Graph showing the measured average value and standard deviation of the N2O gas concentration in the rotation mode [Figure 7] Graph showing the measured average value and standard deviation of the N2O gas concentration in the fixed mode [Figure 8] Schematic diagram showing the configuration of the gas cell and chamber in a single gas cell system [Figure 9] Schematic diagram showing the configuration of the gas cell and chamber in a rotary multi-gas cell system [Figure 10] Graph showing the measurement results of the N2O gas concentration at different measurement intervals by a single gas cell system and a rotary multi-gas cell system [Figure 11] Image diagram comparing the configurations of a single gas cell system and a rotary multi-gas cell system

Embodiments for Carrying Out the Invention

[0017] The NDIR greenhouse gas monitoring device according to the present invention is composed of a rotary multi-gas cell system and an NDIR sensor system.

[0018] Figure 1 is a schematic diagram showing the general configuration of the rotary multiple gas cell system within the device in question. A rotary multiple gas cell system consists of multiple rotating gas cells. The rotating gas cell consists of four PVC cylinders (each with an inner diameter of 16 mm and a length of 495 mm), arranged around a central axis and secured by gas cell holders attached to both ends of the central axis. The gas cell holder rotates circumferentially around the central axis, causing the gas cell to rotate circumferentially around the central axis.

[0019] As shown in Figure 3, both ends of the gas cell are covered with CaF2 windows (manufactured by Thorlabs: φ25.4 mm, 5 mm thick). Furthermore, as shown in Figure 1, two valves (a gas inlet valve and a gas outlet valve) are provided near both ends of the gas cell.

[0020] The central axis is connected to a digital servo motor (DS3225, torque 25kg, rotation angle 270°), and the output of this motor rotates the central axis, causing the gas cell holder and gas cell to rotate. The digital servo motor's output is controlled by a programmed Arduino Uno Rev3 board (controller). The program allows you to pre-set a measurement schedule at arbitrary time intervals. This allows for automatic measurement of the gas concentration in each gas cell at arbitrary time intervals, eliminating the need for a complex valve system.

[0021] Figure 2 is a photograph used as a drawing substitute, showing the NDIR greenhouse gas monitoring device according to the present invention. The NDIR sensor system that constitutes the NDIR greenhouse gas monitoring device consists of a controller, an "NDIR light source unit" consisting of an NDIR light source and a plano-convex lens as shown in Figure 2, and an "NDIR detector unit" consisting of an NDIR detector, a plano-convex lens, and an optical filter (Fabry-Perot variable filter).

[0022] The NDIR sensor system scans the wavelength range of 3800 μm to 5000 μm, with the NDIR light source and NDIR detector performing infrared light emission and detection, respectively. By using multiple gas cells, separate gases obtained at multiple different measurement points can be circulated without the need for an additional valve system, allowing for the measurement of N2O gas levels at different locations.

[0023] The controller, using a programmed Arduino Uno Rev3 board, controls the motor's output, causing the central axis connected to the motor to rotate or reverse. This allows two or more gas cells fixed to a gas cell holder to be rotated to position them for measuring the intensity of infrared light from an NDIR light source and NDIR detector, and then reversed to return the gas cells to their original positions after the measurement is complete. Furthermore, the controller can be programmed to repeatedly rotate or reverse the central axis connected to this motor at arbitrary time intervals, thereby rotating two or more gas cells fixed to the gas cell holder to position them for measuring the intensity of infrared light from an NDIR light source and NDIR detector, and then reversing the rotation to return the gas cells to their original positions after the measurement is complete, allowing for repeated measurement of the gas concentration in each gas cell.

[0024] The gas inlet and outlet valves of each gas cell, which are the gas inlet and outlet, are connected to a colorless, transparent, flexible gas tube to circulate the gas, and the gas tube is secured to an aluminum socket on the gas cell holder. If only one type of gas is being measured, the NDIR detector and NDIR light source can be combined into a single unit to reduce the size and cost of the device. However, if multiple types of gases are being measured, a multi-gas sensor including a detector, a filter with selectable wavelengths, and a filter wheel is required. Fabry-Perot variable filters selectively transmit only specific wavelengths. By connecting a Fabry-Perot variable filter, which is an optical filter, to an NDIR detector, the absorbance at each wavelength can be detected.

[0025] Figure 3 is a schematic diagram showing the NDIR optical path passing through the gas cell of the NDIR greenhouse gas monitoring device according to the present invention. To focus the infrared light emitted by the NDIR light source, two highly reflective plano-convex lenses (manufactured by Thorlabs: φ25.4mm, F=40mm, CaF2, E-coated) are placed parallel to each other at both ends of the gas cell.

[0026] Infrared light passes through gas cells arranged in a straight line and is focused onto a Fabry-Perot variable filter via a plano-convex lens (manufactured by Thorlabs: φ25.4mm, F=40mm, CaF2, E-coated) placed in front of the NDIR detector. Infrared light emitted from an NDIR light source is reflected between two lenses, allowing a Fabry-Perot variable filter to selectively transmit only specific wavelengths. An NDIR detector, a tunable Fabry-Perot detector (manufactured by Infratech), was used to detect absorbance in the wavelength range of 3800 μm to 5000 μm at 10 μm intervals.

[0027] Furthermore, the intensity of infrared light using an NDIR light source and a tunable Fabry-Perot detector was measured using the Fabry-Perot detector evaluation kit (Infratech, version 3.0). The Fabry-Perot detector evaluation kit allows users to change the frequency of infrared light emitted from an NDIR light source, select the infrared light wavelength range to be detected by the NDIR infrared detector, and record infrared intensity at arbitrary time intervals using the included software.

[0028] Furthermore, when measuring the intensity of infrared light passing through the gas cell, a digital servo motor is used to rotate the central axis, moving (rotating) the gas cell, which is fixed to the gas cell holder, to a position where the intensity of infrared light from the NDIR light source and NDIR detector can be measured. The movement (rotation) of this gas cell is controlled by the output of a digital servo motor controlled by a programmed Arduino Uno Rev3 board.

[0029] Figure 4 shows the temporal relationship in one measurement cycle when an NDIR sensor system and a rotary multi-gas cell system are synchronized. The interval for switching between multiple gas cells and the waiting time for measurement at the installation location of each gas cell in the NDIR sensor system can be adjusted by program. Once a gas cell is installed in the NDIR sensor system, the Fabry-Perot detector evaluation kit software initiates a measurement process to obtain spectra at each wavelength step (10 μm intervals between 3800 μm and 5000 μm).

[0030] The waiting time for the NDIR sensor system before starting the next measurement can be arbitrarily adjusted using the software in the Fabry-Perot detector evaluation kit. The waiting time can be adjusted depending on the requirements of the measurement interval (e.g., N2O gas measurement every 30 minutes) and the nature of the experiment.

[0031] Figure 5 is a schematic diagram showing the installation position and rotation direction of the gas cell. Rotating multi-gas cell systems cannot continuously rotate in one direction because flexible gas tubes for gas circulation, fixed to an aluminum base, are connected to the gas cells. Therefore, the rotating multi-gas cell system starts rotating counterclockwise, for example, from gas cell 1 to gas cell 4. Once the step of measuring the spectrum at each wavelength step (10 μm intervals between 3800 μm and 5000 μm) at the alignment of each gas cell is completed, the rotating multi-gas cell system rotates clockwise back to its original position (arrangement). One cycle is defined as completing the measurement of all gas cells and then rotating in the opposite direction to return to their original position (arrangement). The next cycle will begin after the device's standby time is over and will rotate in the same way as the first cycle.

[0032] An experiment to confirm the accuracy of the NDIR greenhouse gas monitoring device according to the present invention was conducted as follows. The experiment was conducted by dividing the operating mode of the NDIR greenhouse gas monitoring device according to the present invention into two stages.

[0033] One operating mode is the "rotation mode," in which four gas cells are rotated and used sequentially for measurement, while the other operating mode is the "fixed mode," in which only one gas cell is used continuously for measurement without rotating the gas cells. The "fixed mode" refers to the conventional measurement method using a single gas cell, while the "rotating mode" refers to the measurement method using multiple rotating gas cells according to the present invention.

[0034] Since the experiment required multiple measurement points, two chambers with different N2O gas concentration conditions (Chamber 1: 0 ppm, Chamber 2: 200 ppm) were used, and the gas concentration in each chamber was measured over time. Furthermore, when all four gas cells are used, it is possible to simultaneously measure spectra at four different wavelength steps (10 μm intervals between 3800 μm and 5000 μm).

[0035] In "fixed mode," as shown in Figure 8, a single gas cell is used to measure the gas concentration in two chambers. This is achieved by switching the gas tubes that connect the inlet and outlet of the single gas cell to the inlet and outlet of each chamber. Chamber switching solenoid valves and gas cell switching solenoid valves were used to switch between gas tubes. A gas circulation pump was used to circulate the gas between the chamber and the gas cell.

[0036] In the "rotation mode," as shown in Figure 9, four gas cells are used to measure the gas concentration in two chambers. For each chamber, the inlet and outlet are connected by gas tubes to the gas inlet valve and gas outlet valve of a separate gas cell (hereinafter, "the ○th gas cell" will be referred to as "gas cell ○"). A gas circulation pump was used to circulate the gas between the chamber and the gas cell.

[0037] Furthermore, the measurement intervals were set to 15 seconds, 30 seconds, 60 seconds, and 120 seconds, and Figure 10 shows the results measured at four different intervals in a graph ((a) 15 seconds, (b) 30 seconds, (c) 60 seconds, (d) 120 seconds). Once the measurement was complete, in fixed mode, the chamber was switched using a solenoid valve; in rotating mode, the gas cell was rotated to switch.

[0038] In all experimental modes, N2O gas packed into the gas cell was circulated within the apparatus, and data was recorded as the detector output. Using a calibration model, N2O gas at four concentration levels (15.7 ppm, 37.3 ppm, 83.5 ppm, and 127.2 ppm) was measured 15 times consecutively. The experimental results, including the average and standard deviation of measurements at each concentration level, are shown in Table 1.

[0039] [Table 1]

[0040] In addition to Table 1, the average and standard deviation of N2O gas concentrations measured in rotation mode are shown in Figure 6, and the average and standard deviation of N2O gas concentrations measured in stationary mode are shown in Figure 7. These results show that, regardless of the operating mode, higher concentrations of supplied N2O gas resulted in higher measured values, but the rotation mode showed a greater deviation than the fixed mode. This is thought to be due to tuning errors in the digital servo motors used to repeatedly reposition multiple gas cells to match the positions where the intensity of infrared light from the NDIR light source and NDIR detector is measured.

[0041] Furthermore, in rotation mode, we believe that the standard deviation of the measured values ​​for each gas cell is carried over even when the gas cell is switched, which is another contributing factor. However, we believe that this can be minimized by using a high-precision motor to rotate the rotary multi-gas cell system and a controller to control the motor's output.

[0042] Furthermore, the results measured at four different measurement intervals in Figure 10 show that in rotation mode (meaning "bottom: rotating gas cell" in Figure 10), no fluctuations were observed in the measured values ​​at all measurement intervals from (a) to (d), and they remained constant (200 ppm or 0 ppm). This is because a separate gas cell was used for each chamber.

[0043] In contrast, in the fixed mode (meaning "Top: Single Gas Cell" in Figure 10), the measured values ​​fluctuated between 200 ppm and 0 ppm at all measurement intervals from (a) to (d). In particular, the measured value in Chamber 1, where the N2O gas concentration condition was 0 ppm, should have been 0 ppm, but the shorter the measurement interval, the less it dropped to 0 ppm.

[0044] This is because, due to the short measurement interval, the gas remaining in the gas cell after it was switched by the gas cell switching solenoid valve was measured. In other words, with conventional gas measurement methods using a single gas cell at multiple locations, such measurement results can occur when the measurement interval is short. Furthermore, even in the fixed mode, with measurement intervals longer than (a) and (b) (c) and (d), the measured values ​​in Chamber 1, where the N2O gas concentration is 0 ppm, begin to decrease from the start of measurement and remain constant from the middle of the measurement.

[0045] These results indicate that, for gas measurements at multiple locations, the measurement method using multiple rotating gas cells according to the present invention can provide more accurate measurements than the conventional measurement method using a single gas cell. In particular, the NDIR greenhouse gas monitoring device according to the present invention enables gas monitoring at multiple locations with fewer resources (excluding additional gas sampling units and valve systems) by using multiple gas cells.

[0046] Furthermore, when switching gases at each measurement point, measurements can be taken simply by rotating multiple gas cells with pre-installed chambers, eliminating the need to replace the gas within the gas cells. As a result, the required observation time at each measurement point is short, and gas switching can be performed in a short time. Furthermore, by programming and controlling the measurement schedule, it becomes unnecessary to use a complex valve system, and electromagnetic valves for switching gases at each measurement point are also unnecessary, resulting in a reduction in scale and power consumption. For example, in measurements at four locations, as shown in Figure 11, the NDIR greenhouse gas monitoring device according to the present invention requires only four 4.2W pumps, whereas a conventional single-gas cell system requires one 4.2W pump in addition to eight 12W solenoid valves.

[0047] In this embodiment, a rotary multi-gas cell system was synchronized with an NDIR sensor system using a timer. The synchronization of the NDIR sensor system and the rotary multi-gas cell system is performed by a timer-based program, which can be adjusted according to the required measurement schedule and measurement locations. Note that the calibration and adjustments required to measure the intensity of infrared light (for example, the process of leveling during surveying) are omitted from the explanation.

[0048] In this embodiment, four gas cells were used, but the number of cells can be increased or decreased as needed. When increasing the number of cells, it is desirable to increase the diameter of the gas cell holder, lengthen the circumference of the gas cell holder, and use a high-precision, powerful motor.

[0049] Furthermore, two or more rotary multiple gas cell systems according to the present invention can be used simultaneously. A high-precision geared stepper motor or a similar high-precision mechanical power source can also be used to rotate the gas cell.

[0050] By adding a set of reduction gears, it is possible to maintain a high ratio of motor shaft rotation speed to the rotational multi-gas cell system. Stepping motor drivers can improve the accuracy of rotational systems by converting pulse signals into angular displacement signals.

[0051] The NDIR greenhouse gas monitoring device shown in the example in Figure 2 is designed to be 750mm long, 300mm wide, 300mm high, and weigh 6kg, so it can be transported to agricultural sites by hand. The NDIR greenhouse gas monitoring device according to the present invention requires low power from the NDIR sensor system, the rotary multi-gas cell system, and the gas circulation pump (12V, 5A), and can therefore be used in remote locations using an auxiliary battery power source such as a solar panel.

Claims

1. Two or more gas cells are provided, each equipped with a gas inlet valve and a gas outlet valve, which are the gas inlet and outlet. A gas cell holder that secures both ends of each gas cell, The central axis that serves as the axis of rotation for the gas cell holder, A motor connected to the central axis, which rotates the gas cell holder by rotating the central axis, A chamber connected by a gas cell and a gas tube, A rotary multiple gas cell system having, An NDIR light source unit comprising an NDIR light source that emits infrared light and a plano-convex lens that focuses the light emitted by the NDIR light source, An NDIR detector unit comprising an NDIR detector for detecting infrared light, a plano-convex lens for focusing light emitted by an NDIR light source that has passed through a gas cell, and an optical filter connected to the NDIR detector for detecting the absorbance of each wavelength, A controller that controls the output of the motor that rotates the central axis in a rotary multi-gas cell system, An NDIR type sensor system having, Composed of, By rotating two or more gas cells that circulate gas between a chamber connected to the gas cell, and using an NDIR light source and an NDIR detector to emit and detect infrared light, The gas concentration in a chamber containing the target gas at multiple measurement points can be measured without replacing the gas in the gas cell. An NDIR greenhouse gas monitoring device characterized by the following features.

2. Two or more gas cells are provided, each equipped with a gas inlet valve and a gas outlet valve, which are the gas inlet and outlet. A gas cell holder that secures both ends of each gas cell, The central axis that serves as the axis of rotation for the gas cell holder, A motor connected to the central axis, which rotates the gas cell holder by rotating the central axis, A chamber connected by a gas cell and a gas tube, A rotary multiple gas cell system having, An NDIR light source unit comprising an NDIR light source that emits infrared light and a plano-convex lens that focuses the light emitted by the NDIR light source, An NDIR detector unit comprising an NDIR detector for detecting infrared light, a plano-convex lens for focusing light emitted by an NDIR light source that has passed through a gas cell, and an optical filter connected to the NDIR detector for detecting the absorbance of each wavelength, A controller that controls the output of the motor that rotates the central axis in a rotary multi-gas cell system, An NDIR type sensor system having, Composed of, The controller in question is, The system has a function to control the rotation of two or more gas cells, fixed to a gas cell holder, to the position where the intensity of infrared light from an NDIR light source and an NDIR detector is measured, and to return them to their original positions after the measurement is complete, using the output of a motor. By circulating gas between the gas cells and a chamber connected to them, and rotating two or more gas cells positioned at the measurement location, infrared light emission and detection are performed using an NDIR light source and an NDIR detector, The gas concentration in a chamber containing the target gas at multiple measurement points can be measured without replacing the gas in the gas cell. An NDIR greenhouse gas monitoring device characterized by the following features.

3. Two or more gas cells are provided, each equipped with a gas inlet valve and a gas outlet valve, which are the gas inlet and outlet. A gas cell holder that secures both ends of each gas cell, The central axis that serves as the axis of rotation for the gas cell holder, A motor connected to the central axis, which rotates the gas cell holder by rotating the central axis, A chamber connected by a gas cell and a gas tube, A rotary multiple gas cell system having, An NDIR light source unit comprising an NDIR light source that emits infrared light and a plano-convex lens that focuses the light emitted by the NDIR light source, An NDIR detector unit comprising an NDIR detector for detecting infrared light, a plano-convex lens for focusing light emitted by an NDIR light source that has passed through a gas cell, and an optical filter connected to the NDIR detector for detecting the absorbance of each wavelength, A controller that controls the output of the motor that rotates the central axis in a rotary multi-gas cell system, An NDIR type sensor system having, Composed of, The controller in question is, Two or more gas cells fixed to a gas cell holder, Rotate the NDIR light source and NDIR detector to position them for measuring the intensity of infrared light. After the measurement is complete, rotate it in the reverse direction to return it to its original position. Repeating this multiple times It has a function that controls the motor output, By circulating gas between the gas cells and a chamber connected to them, and rotating two or more gas cells positioned at the measurement location, infrared light emission and detection are performed using an NDIR light source and an NDIR detector, The gas concentration in a chamber containing the target gas at multiple measurement points can be measured without replacing the gas in the gas cell. An NDIR greenhouse gas monitoring device characterized by the following features.

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